1. Field of Invention
The present invention pertains to the field of processors. More particularly, this invention relates to instruction execution in a processor.
2. Art Background
A computer system usually includes one or more processors which execute instructions. A processor may also be referred to as a central processing unit. A typical processor fetches a stream of instructions from a memory and executes each instruction in the instruction stream.
Typically, the instructions in an instruction stream have dependencies with respect to one another. For example, it is common for an instruction in the instruction stream to use the results of one or more previous instructions in the instruction stream. It is therefore common for a processor to stall instruction execution whenever the result of a previous instruction is not available for use by a subsequent instruction that requires the result.
Some instructions can cause a processor to stall instruction execution for a relatively long time. Such instructions may be referred to as high latency instructions. Unfortunately, the relatively long duration stalls caused by high latency instructions can greatly diminish the overall instruction execution performance of a processor.